Well tool



March 26, 1935.

WELL TOOL Filed July 50, 1952 3 Sheets-Sheet 1 WELL TOOL Filed July 50, 1932 3 Sheets-Sheet 2 March 26, 1935. J. H. HOWARD WELL TOOL Filed July 5o, 1932 s sheets-sheet s Patented Mar. 26, 1935 UNITED STATES PATENTy OFFICE -13 Claims. (Cl. Z55-72) Thisinvention relates to a well tool and relates more particularly to a core bit or drill.

A general object of the vinventioniis to provide a simple, practical and eiectiv'ewell core drill and to provide a dependable and effective means for 'detachably mounting cutters in such a tool.

An object 4of this invention is to provide -a simple and inexpensive means for dependably and effectively mounting a cutter on a welldrilling tool.

Another object rof the invention is to provide a Well core drill comprising a one ipiece head and a plurality of cutter units or assemblies detachably mounted on the head.

It is another object of the invention to provide a core drill of the character mentioned in which the cutter units or assemblies can be attached to or mounted on the head of the drill as individual units.,

It is another object of the invention to provide a core drill of the character mentioned in which roller cutters may be easily and conveniently mounted on the head or body of the drill and may be easily and quickly detached for replacement, repair, etc.

It is another object of the invention to provide a core drill of the character mentioned in which the -cutter assemblies may be easily and quickly slipped into position vin openings in the head of the-drill and then dependably locked in place by pins whichare not subjected to any of the working or cutting strains.

, It is a furtherobject of the invention to provide acoreV drill in which the cutters are rotatably carried by heavy, long wearing shafts or pins each-having portions of different diameters ,.with a thrust shoulder between them, which shafts or pins are dependably and positively held against accidental displacement or detachment from the tool. l

It is a. further object of the invention to provide a core drill comprising aone piece head and a. plurality of detachable segments on the lower end of the head .each carrying a detachable cutter unit.

Other objects and features of the invention will be best and more fully understood from the following detailed description of typical forms and applications of the invention, throughout companylng drawings, in which:v Fig. 1 is a side elevation of one forni of th sectional view of the lower end portion Iorf-the .fications that may fall within which description reference is had to the ac-l tool illustrated in Fig. 1. Fig. 3 is a bottom elevation, .being a viewtaken as indicated by line 3-'3 on Fig. 2. Fig. 4 is an enlarged side elevation of one of the cutter carrying,'shafts or pins. Fig. 5 is an end view of the pin, being a view 5' .taken as indicated by line 5-5 on Fig. 4. Fig.

6 -is an end view of the washer embodied in the cutter assembly. Fig. 7 is an enlarged fragmentary side elevation of thetool illustrating one of the cutter units, and the adjacent portion of l0 the head. Fig. 8 is a fragmentary vertical sectional view taken as indicated by line -8--8 on Fig. 7 showing a portion of the head with the cutter assembly removed. Fig. 9 is a transverse sectional View of the washer, being a view taken 15 as indicated by line 9 9 on Fig. 6.v Fig. 10 is a vertical detailed sectional view of the lower end portionof another form, of core drill. Fig. 11 is a transverse detailed sectional view taken as indicated by line 11-11v on Fig. 10. Fig. 12 20 is an enlarged vertical detailed sectional -view of one of the detachable wings or segments of the tool illustrated in Fig. 10 showing it with the cutter assembly removed, and Fig. 13 is a transverse sectional `view taken as indicated by line 13-'13 on Fig. 12. l

In accordance with the broader aspects of the invention, the detachable cutter units provided A bythe invention may be embodied in or applied to various classes of well tools, and may be modifled to adapt them for use in various tools. Throughout the following detailed disclosure of. the invention, I will conne the description to two typical applications and embodiments, itbeing understood that the invention is not to'be con- 35 strued as limited or restricted to the forms or specific details about to be described,-but that it is to be taken as including any features or modithe scope of the claims.

The embodiment `of my invention illustrated in Figs. 1 to 9 of the drawings includes, generally, an outer barrel 10, an inner-barrel or core barrel 11, a core catcher 12, a head 13, and a plurality of detachablev cutter units 14 on the lower end 45 of the head. l l

vThe outer barrel 10 of the core drill lis anelongated tubular member adapted to be connected with the lower end of an operating stringof drill pipe, or the like. The outer barrel 10 may-be 50 connected with the operating string through a drill collar 1.5,. A sub or tubular" connecting member 16 ,isprovided .onthe lower end ofthe outer barrel l0 and is provided at its lower end with a screw-threaded pin 1'7. 55

The inner barrel liis provided to receive and hold the core and isl disposed within the outer barrel 10. 'The barrel 11 extendslongitudinally and 'centrally through. the outer barrel 10 and is spaced from'tlxe interior of the barrel 1 0 to provide an annular fluid passage between the barrels; A lower sub or connecting member 18 has a threaded socket 19 receiving the pin 17 and carriesthe inner barrel 11. The core barrel 11 extends downwardly throughthe upper sub -16 and its lower 'end is screw-threaded into the opening 20 in the lower sub 18. 'I'he lower end of the barrel 11 Iprovides a downwardly facing shoulder 21 in the sub 18, and the lower end of the barrel 11 is of course open to receive the core. A downwardly and inwardly inclined shoulder 22 is provided in the lower-end of the opening 20 of the lower sub 18. Y

The core catcher 12 is provided to grip the core and to aid in breaking thecore away from the formation in the bottom of a well-bore and acts `tc support or hold thecore in the drill when the drill is withdrawn from the well.- In accordance with the broader principles of the invention, any suitable or desirable form of core catcher mayy be lembodied in the drill. The particular core catcher 12 illustrated in the idrawings is fully describedl and claimed in theco-pending application of J. H. Howard and A'. C. Catland entitled Core catcher, Serial No. 666,482, filed March 18, 1933, includes connected rings 23 and 26 shftable orslidable longitudinally in the opening 2,0 between the shoulders 21 and 22.

Circumferentially 'spaced `flat springs or leaf springs 25v are rcarried by the ringr 23. The springs 25 are gripped between the ring 23 and aninner ring 26 and project from the upper and lower2 ends of the rings. The opening 24 in theinner ring 26 is of substantially the same diameter as the opening in the c ore barrel 11 so`that` it will readilypass the core upwardly into the barrel. The upper projecting ends of the springs 25form spring fingers for engaging the/coreand are bent or bowed inwardly. The upper ends of the'sprlng fingers may be pointed and bifurcated as shown inFig. 2 of the drawings. Gripping dogs or slips 27 are attached to the projecting lower ends of the springs 25. The outer sides of the slips 27 are tapered to effectively cooperate with' the .tapered shoulder 22.

- Suitable gripping teeth or ribs are provided on the inner sides of the slips 27 to bite into or en-4 gage the core.- Upon upward movement of the tool, the spring fingers are adapted to yieldingly engage the core to hold the ring 23 against movement with the rest of the tool so that the tapered shoulder 2,2 is brought into active wedging engagement with the'slips 27 to force them into. gripping and holding engagement with the core so that the slips are operable to break the core away from the `formation and support the core in the drill. g

The head 13 is attached toror Amounted on the lower end of the sub or intermediate member 18- and is provided primarily to support orcarry the cutting' units 14. vIt is a feature ofthe invention that the head 13'y is a one-piece or integral member and of s ple formation. In the particular embodiment, f the invention being described, a tapered pin 28 on the' lower end of thesub 18 is threaded into a socket 29 inthe upper end .of the head to attach the head to, the sub. The

upper 'end of the head 13' seats against a-slioul-fn der 30 at the base or upper end of thetitperel-4 pin 28. The head B is an -annular or tubular member having a central vvertical opening 31 aligned with or co-axial with theopenings in the subs 17 and 18 andthe opening in the core barrel 11. Tile head 13 has comparatively heavy or thick walls and a plurality of circumferentially spaced enlargements or projections 32 are provided on the exterior of the head. The enlargements 32 extend upwardly from the lower end of the head 13 and are spaced apart to provide vertical grooves 33 in the exterior of the head 13 for the upward circulation of the circulating fluid. A plurality of sockets or openings 34 and 35 are provided in the lower end of the head 13 to carry the cutting units 14. The openings 34 and 35 are provided in the head 13 at or immediately in/wardly ofthe enlargements 32 and are shaped to receive the cutter units 14 as-will be more fully described in connection with the description of the cutting units. The number of openings 34 and 35 of course depends upon the number of cutter units.

The cutter units or cutter assemblies 14 and -the manners of detachably holding or mounting them in the openings 34 and 35 are important features of the invention. The cutter units 14 may involve cutters of different sizes and cutters of dierent characters, shapes, etc. The cutter mountings or the means for mounting the c'utters of the units 14 are particularly adapted to rotatably support roller cutters of the character commonly employed in rock core drills. In the specific embodiment, of the invention illustrated in Figs. 1 to 9 inclusive of the drawings, there are six cutter units 14 on the lower end of the head I3, three unitsor assemblies A involving outer cutters B for acting on the formation at the bottom of the well bore and side wall of the well bore to cut the bore to size, and three assemblies C, each involving an irmer cutterfD for acting on the formation at the bottom of the well bore and for cutting or trimming the core. It is to be lunderstood that the present invention may be embodied in well t'ools involving various numbers ofcutting units, `for example, it may be advantageously embodied in a tool havingfour outer specific application of the invention illustrated in the' drawings;

In the typical form of the invention being'described, the drill embodies six cutter units 14 for mounting'invthe openings 34 and 35 in the lower end of the head 13. There may be three equally Yspaced openings 34 and three equally spaced openings in the lower end of the head. The outer cutter assemblies A are carried in the openings 34 which are spaced substantially 120 apart, while the inner cutter units C are carried `in the openings 35 which are spaced between the said openings 34 so that they too are spaced substantially 120 apart. As the invention contemplates various different numbers and characters of cutters and various manners of spacing. and relating the cutters, the invention is/'not to be taken as limited to the specific arrangement just set forth.

The Openings 34 for carrying the outer cutter units A, have ,their inner and outer walls 37 inclined downwardly and outwardly. The openings 34 extern'l upwardly into .the lowervend of the 13 and their upper walls 36 may slope upoutwardly.'- In\the preferred concieincnaed andcuter end walls 37 of the openings 34 are substantially flat and parallel as illustrated in detail in Fig. 8 of the drawings. The openings 34 are provided in the head 13 at points inward of the enlargements 32 and the sides of the openings 34 are open at the vertical fluid passing grooves 33 in th'e exterior of the head 13. In accordance with the invention the openings 34 are positioned in the head so that there is considerable stock or material in the wall of the head at the inner ends of theing pins 38 are detachably mounted inthe head inner walls. 50

13 so that they are positively held against rotation and so that the operating or drilling thrusts are transmitted directly from the pins to the head. Slots 39 are provided in vthe lower end of the head 13 to receive the pins 38. The pin canying slots 39 intersect the openings 34 and have their aligned ends extending through the parallel side walls 37 of the openings. In accordance with the invention the slots 39 are rectangular or have at parallel and substantially vertical side walls and are open at their lower ends. Enlargements 40 are provided at the opposite ends of the slots 39. The sockets or enlargements 40 may be round or partially round as illustrated throughout the drawings. As the slot enlargemen'ts 40 are larger than the slots 39 and are spaced from the opposite side walls of the openings 34, lugs 40a are formed on the walls of the slot enlargements 40 at .the side walls of the openings 34.

The cutter carrying pins 38 are shaped so as to i'lt into the rectangular or squared slots 39. Diametrically opposite cuts or notches 41 are provided in each pin 38 at points spaced a short distance from its opposite ends. 'I'he cuts or` notches 41 in the pins are polygonal or squared, having parallel side walls and flat b ottoms or In accordance with the invention the slots 39 in the head and the notches 4l in the pins 38 are proportioned and related so that the pins may be slid ,or passed upwardly into slots 39 so that the slots 39 and 41 cooperate, that is so that the notches 41 receive the'lugs 40a. Due to this relationship, the end portions of the pins 38, that is, the portions of the pins extending outwardly from the notches 41 fit inthe slot enlargements 40 of the head and the inner walls or bottoms of the pin slots or notches 4l cooperate 'with the verticall walls of the slots 39. In this manner the cutter carrying pins 38 are positively held against rotation and longitudinal movement.

It is to be noted that the flat walls of the pin grooves or notches 41 cooperate with the flat parallel walls 37 of the head openings 34 so that longitudinal thrusts on the pin are transmitted directly to the head 13.', 'I'he outer ends of the pins 38 may be bevelled oi or inclined to lie ush with the outer sides of the headvenlargements 32, while the inner ends of the pins 38 may be shaped to have portions flushwith the wall of the head opening 31, and with the lower end of the head In accordance with the invention, each of the cutter carrying pins 38 is provided intermediate its ends with a bearing enlargement 42. The enlargements 42 have their inner ends adjacent to or coincident with the'walls of the linnermost pin slots 41 so that their ends are adapted to engage the inner walls 37 of the head openings 34. The bearing enlargements 42 provide outwardly facing thrust shoulders 43 on the pins 38 that may be bevelled or'tapered as illustrated in-Fig. 4 of the drawings. are preferably hardened so as to be particularly long wearing.

The outer cutters B which are rotatably carried by the pins 38, are in the nature of roller cutters. In the particular case illustrated in the drawings, the outer cutters B are substantially frusto-conical in their general conguration having 'their peripheries inclined relative to their longitudinal axes. The central openings 44 in' the cutters B are each provided with an enlargement 45 for re- `ceiving the bearing enlargement 42 of a pin 38. It will be apparent how the thrust shoulders 43 of the pins cooperate with the shoulders in the cutters that 'occur at the ends of the cutter opening enlargements 45. 'I'he outer end of each cutter B is recessed as at 46 to receive a washer 47. The washers 47 are adapted to engage or cooperate with slight bosses 48 on the outer walls 37 of the head openings to space the outer ends of the cutters B from the walls of the openings. If desired or found practical, the washers 47 may be welded to the cutter carrying, pins 38. The washers 47 are yprovided with keys or projecting parts 48a that are adapted to engage the body at the lower ends of the slots 39 to positively hold the washers against rotation. The enlarged bearing portions 42 of the cutter carrying pins 38are proportioned so that the'thrust shoulders 43 operate to space the inner ends of the cutters The cutter carrying pins 38 B of the inner walls 37 of the head openings 34.

'I'he roller cutters B are rotatably/.mounted on the inclined pins 38 so that they project down` the cutters B is such'that the peripheries of the" cutters which project downwardly from the lower end of the head` 13 are substantially normal to the longitudinal axis of :the tool. Suitable cutting parts or teeth 49 are provided on the peripheries of the cutters B. In accordance with the invention, the cutting parts or teeth 49 may be straight axial teeth or may be pitched in either direction. Reaming shoulders 50 are provided on the projecting outer ends of the cutters B to act on the formation at thel'side wall of the well bore. It will be apparentl how the rotatable outer roller cutters B are eiective in making an annular cut in the formation and in cutting or reaming the well bore to size. As the cutters B project outwardly beyond the head enlargements 32, they operate to give the tool proper clearance in the well bore.

'Ihe invention provides simple eiective'means for detachably locking the outer cutter assemblies- A in the head openings 34. The releasable gitudinal opening 51. is provided in each of the cutter carrying pins 38. The openings 51 are ec v`centric or offset from the longitudinal axes of the pins 38 and extend completely through the pins from one end to the other. Substantially ses.

semi-circular notches 52 are provided in the walls of the slots 39. A removable pin 53 extends longitudinally 'through each opening 51 and cooperates with the notches 52 to positively hold the cutter assemblies A in their proper positions in the head 13. The lock pins 53 may be easily and quickly passed through the openings 51 to lock the assemblies A in the head. The present invention contemplates retaining the lock pins 53 in positions in various manners, for example, the pins may be screw-threaded into the openings 51 or may be riveted or Welded in position or may be in the nature oi. tapered pins riveted at one end.

vFrom the above detailed description of the outer cutter units A and their detachable connections with the head 13, it will be apparent how the cutter assemblies A may be easily and quickly arranged in positions in the openings 34 and slots 39, and then locked in place by the removable pins 53. The lock pins 53 are not subjected to any of the operating or cutting thrusts, but merely act to hold the assemblies against downward displacement.

The inner cutter assembliesC include the cutters D which are provided to act on the formation at the bottom of the-well bore to aid and supplement the cutters B and to trim or shape the core as it passes into the drill. vThe cutter assemblies C are similar, generally, to the outer cutter assemblies A, that is, they each include a shaft or pin 55 for rotatably supporting the cutter B and a means for directly removably locking the pins 55 in positions where they support the cutters D in the openings 35. The openings 35 for receiving the inner cutters D extend upwardly into the lower end of the head 13 and have inner and outer side walls 56 inclined downwardly and inwardly. The openings 35 are provided at or inward of the enlarged portions 32 of the head 13 andtheir opposite ends are open at the fluid passing grooves 33. The inner walls 56 of the openings 35 join the wall of .the head opening 31 at points spaced above the lower end of the head. Slots 57 are provided in the head 13 to receive and hold the pins 55. The slots 57 extend through or intersect the openings 35 at their inclined walls 56 and have flat vertical or parallel walls. Enlargements 58 are provided at the opposite ends of the slots 57 and being spaced from the walls of the openings to provide lugs similar to the lugs 40a described above.

The cutter carrying pins 55 are shaped to effectively t into the slots 57. Diametrically opposite cuts or notches 59 are provided in each of the pins 55 to receive the lugs on the walls of the slots 57. The slots 57 and the notches 59 cooperate to positively hold the pins 55 against longitudinal movement and rotation. The end portions of the pin 55 are carried in the slot enlargement 58 and the opposite ends of the pins 55 are shaped to lie ush with the inner and outer walls yof the head 13. Each of the pins 55 has an enlarged bearing portion 60 providing an inwardly facing thrust shoulder 61. The slots 57 are inclined upwardly and inwardly so that the pins 55 support the cutters D for rotation about upwardly and inwardly inclined axes.

The particular inner cutters D illustrated in the drawings are cylindrical roller cutters having cutting parts or teeth 62 at their peripheries. The openings in the cutters D which receive the pins 55 are provided with enlargements 63 for receiving the bearing portions 60 of the pins. The enlarged bearing portions 60 of the pins 55 are proportioned so that the cutters D are properly spaced from the outer walls 56 of the openings 35. A thrust Washer 64 is provided on each pin 55 and is received in a socket in the inner end of a cutter D. The washers 64 engage the inner end walls 56 of the openings 35 and are provided with key parts 65 at their ends for engaging the head 13 at the'bottom of the slots 57. The washers 64 may be welded on the pin 55, if desired. The assemblies of the pins 55, cutters D and washers 64 are removably locked in position by lock pins 66 passing through longitudinal openings in the pins 55 and cooperating with notches in the head 13 in the same manner as the lock pins 53 described above. The cutters D are proportioned and mounted so that their peripheries project downwardly from the lower end of the head 13 to engage the formation at the botom of the well bore Vand project inwardly to project into the opening 31 to cut a round core. The inner and outer cutters B and D overlap one another in their action on the bottom of the bore, so that they are effective in making an annular cut. The cutter assemblies C may be easily and quickly assembled on the head 13 in their proper positions and then locked in placed by the pins 66.

The invention includes meansfor circulating fluid through the drill and for ushing the cutters B and D. An annular groove 70 is provided in the upper end of the head 13 at the shoulder 30. A plurality of spaced iiuid passages 71 extend through the sub 18 from the lower end of the socket 19 to the shoulder 30. Circumferentially spaced fluid passages 72 are provided in the, head 13 and extend downwardly from the groove 70 to the upper ends of the openings 34 and 35. Circulation fluid discharged downwardly through the passages 71 and 72 acts to effectively ush the cutters B and D and is free to pass upwardly between the cutters through the grooves 33.

It is believed that the utility and practicability of the embodiment of the invention illustrated in Figs. 1 to 9 of the drawings will be readily apparent from the foregoing detailed description. In assembling the drill, the cutter units A and C may be assembled and then arranged in position in the head 13 as units. The cutter assemblies A may be readily passed into the openings 34 so that the pins 38 are received and fitted in the slots 39. Lock pins 53 may then be arranged through the openings 51 to lock the assemblies in position. In a similar manner, assemblies C may be arranged in the openings 35 as units and locked in position by means of the lock pins 66. When it is desired to remove the cutter units, the pins 51 and 66 are withdrawn, permitting the easy removal of the assemblies A and C. During operation, the core drill is rotated by the operating string of drill pipe and the cutters B and D act to make an annular cut in the formation so that a core passes upwardly through the openings 31 and 20 and then into the inner barrel 11. Circulation fluid is passed downwardly through the drill pipe under pressure to discharge from the openings 72 and iush the cutters. When a core of the desired length has been cut, the drill is raised and the core catcher 12 grips the core and breaks it away from the formation and then supports it in the core barrel 1l so that it is removed together with the drill.

1t is to be noted that the cutter units A and C are detachably mounted in the one-piece head 13 in a simple and eiective manner. The means for detachablyand rotatably supporting the cutters each involves only a single shaft or pin, a washer and lock pin. The operating or cutting thrusts are transmitted directly from the cutter carrying'pins to the head 13 andthe retaining means does not involve any screw-threaded parts or the like, that are subjected to heavy thrusts. As the detachable cutting assemblies A and C may be easily and quickly assembled on the head 13 as units, the tool is quickly assembled and may be readily provided with new cutters.

The embodiment of the invention illustrated in Figs. 10 to 13 of the drawings involves a cutter head having a plurality of detachable wings or segments each supporting a, removable cutting assembly. This form of the. invention includes generally, a. body or head 75, a plurality of wings or.segments 76 detachably mounted on the lower end of the head, and removable cutter assemblies 77 and 78 carried by^the segments 76.

The head is a one-piece tubular member adapted to be attached to the lower end of the core drill. In accordance with the broader aspects of the invention, the head 75 may be mounted on the lower end of a core drill in any suitable manner, foi` exam le, it may be connected with the outer barrel of a drill by means of any suitable sub or connecting member. The

opening 79 in the head 75 is provided at its lower end with a reduced or restricted' portion 80 and has a downwardly and inwardly tapered shoulder 81 above the restricted part 80. The lower end of an inner barrel or core barrel 82 may be screw-theaded into the upper end of the opening 79. A core catcher 83 is provided in the head opening 79. The core catcher 83 may be of the same construction and operation as the core catcher '12 described above that is, it may comprise a ring 84 slidable in the opening '79, spring lingers on the ring for engaging the core, and slips 86 adapted to-cooperate with the shoulder 8l to grip and hold the core. Circumferentially spaced enlargements 87 are provided on the exterior of the head 75 adjacent its lower end. The lower end of the head 75 may be flat, and a plurality of circumferentially spaced sockets 88 extend upwardly in the head from itsV lower end.

The wings or segments 76 are detachably mounted on the lower end of Vthe head 75 and carry the cutter assemblies 77 and 78. 'Ihe wings 76 are segmental in horizontal cross section and have :dat radial ends 89. In accordance with the invention, the segments 76 are arranged and mounted on the head 75 to have their ends 89 in abutment so that they form a continuousannular assembly on the lower end of the head. 'I'he outer portions of the segment ends 89 may be bevelled or cut away to provide a plurality of circumferentially spaced grooves 90 in the periphery of the assembly to pass circulation fluid upwardly. Pins or studs 91 are provided on the upper=ends ofthe wings 76 and extend into the' sockets 88. Lock through openings in the head 75 with notches 93 in the studs 91 lock the studs in the sockets 88. Rectangular or squared keys 94 are provided on theupper ends of the segments 76 and cooperate with correspondingly shaped key ways 95 in the lower end of the head- 75- to lock the segments against rotation.

The present invention contemplates the provision of cutters of Various' characters, sizes, etc., in the cutter assemblies 77 and 78, and accordingly andY cooperate pins 92 extend' to removably the structure and arrangement of the assemblies 77 and 78 and their mode of attachment tothe segments 76 may be somewhat varied. The par-4 ticular core-drill head illustrated in Figs. 10 to 13 of the drawings involves a plurality of outer cutter assemblies 77 and a plurality of inner cutter assemblies 78 spacedbetween the assemblies 77. The cutter assemblies 77 and 78 are detach= ably mounted in wings or segments that are equally spaced apart, that is, they are carried by alternate wings or segments.

Each of the outercutter assemblies 77 includes a cutter 9'6 and a. shaft or pin 97 for rotatably carrying the cutter 96. The segments 76 carrying the cutting units 77 are each provided at their lower end with an opening 98. 'I'he openings 98 are shaped to eiectively receive the cutters 96 and have end walls inclined upwardly and inwardly. Upwardly and outwardly inclined slots 99 intersect the openings 98 at their inclined end walls and lugs 99a are provided on the walls' of the slots 99 at the opposite walls of the opening 98. The lugs 99a have dat vertical sides. The

`cutter carrying pins 97 areprovided withdia metrically opposite cuts or notches 100 adapted to cooperate withor receive the lugs 99a. The congurations of the slots 99 and the notches 100 corresponds to those of the slots 39 and 41 described above. `The pins 97 are carried in the slots 99 so that they are inclined upwardly and outwardly and therefore support the cutters 96 for rotation about axesinclined upwardly vand outwardly. Washers 101 corresponding in configuration and purpose to the washers 47 are provided on each of the pins 97. The cutter assemblies 77 are locked in position by removable pins 102 extending through eccentric openings in the pins 97 and cooperating with the notchesin the segments 76. Y

The cutters 96 are provided with openings shaped to eifectively pass the pins 97 and their cutter 105 and a pin or shaft 106 .rotatablysupporting the cutter. The segments 76 carrying the vcutter assembly 78 are. each provided with an opening 106e for receiving the cutter 105. The openings 106a extend upwardly into the lower lends of the segments 76 and are provided with downwardlyand inwardly inclined inner and outer walls. Slots 107 intersect the openings 106a and lugs similar to the lugs 99`are provided on the walls of the slots. The slots 107 are provided .to-carry the pins 106 and are substantially normal to the inclined walls of the openings, that they are inclined upwardly and inwardly. T he pins 106 are provided with notches'109 receiving the lugs on the walls 'of the slots 107 'so asto hold`the pins against rotation zand longitudinal movement. The cutter carrying pins 106 are provided with enlarged bea'ring' portions 110 and the openings in the cutters 78 are shaped to effectively receive and pass the pins and their enlargements. Thrust washers 111 similar to the washers 64 are provided on the pins 106.A The cutters 105 may be.

f lower ends of the cylindrical and project downwardly from the segment 76 and 'inwardly into the opening formed by the segments so as to make an annular cut in the formation and form ay core. The cutter Aassemblies 78 are detachably locked in position in the segments 761 by removable pins 115 extending through eccentric openings in the pins 106 and cooperating with segments at the slots 107. Longitudinal fluid es 116 extend through the vhead 75 and communicate'at their lower ends with fluid passages 117 in the segments 76. The openings 117 communicate at their lower ends with the cutter carrying openings 98 and 106* so as to discharge the circulation fluid downwardly against the cutters 96 and 105.

In the form of the invention illustrated in Figs. 10 to 13 of the drawings, the cutter assemblies 77 and 78` may be readily mounted on the segments 76 as units. The assemblies may be easily detached from the segments by removing the locking pins so that the new cutters may be provided onA the segments. If desired, the segments 76 may be removed from the head 75 by withdrawing the removable locking pins 92. The detachable mountings of the cutter assemblies 77 and 78 are particularly simple and eilective and are such that the worlnng or cutting thrusts are transmitted directly from the cutter carryins pins to the segments 76.

Having described only typical, preferred forms and applications of my invention, I do not wish t0 .limit myself to the speciiic details set forth,.but

wish to reserve to myself any changes or variations thatmayappeartothoseskilledintheartor fall within the scope of the following claims.

Having described my, invention, I claim: 1. A core drill including a head having a longitudinal core opening and an opening in its lower end, there beingfaligned slots i opposite walls of the last mentioned opening; lugs on the walls of the slots, and a cutter unit including4 a pin, and a cutter rotatable on the pin, thepin having spaced notches, the said lugs cooperating with the said notches to hold the pin against rotation and longitudinal movement in a position where it extends through the last mentioned opening to support the cutter therein.

- 2. A core drill including a head havinga longitudinal core opening and an opening in its lower end, there being aligned slots in opposite wells of the last mentioned opening. projections on the walls of the slots, and a cutter unit including a pin, and a cutter rotatable on the pin, the pin having spaced notches, the said projections cooperating -with the -said notches to hold the pin against rotation and longitudinal movement in a position where it extends through the last mentioned opening to support the cutter therein, the pin and cutter thereon being adapted to be handled yas a unit when mounting thcutter unit on the head and when dismounting the cutter unit from the head.

3. A core drillincluding end, there being aligned slots in opposite walls of the last mentioned opening, lugs on the walls of the slots, a cutter unit including a pin, and a cutter rotatable on the pin,l the pinv having notches, the said lugs extending into said notches t0 hold ythe pin against rotation and longitudinal movement in a` position where it extends through tnelast mentioned `opening to support the cutter I therein, and Aa removablepart'retaining the pin in the said position where the lugs cooperate with the notches.v

, a head having a longis tudinal core opening and am opening in its lower .theheadasaunlt 4. A core drill including a head having a longitudinal core opening and an` opening in its lower end, there being aligned slots in opposite walls of the last mentioned opening, a'lug on a wall of each slot, a cutter unit including a pin extending into the slots, and a cutter rotatable on the pin, the pin having notches, the lugs cooperating with said notches to hold the pin against rotation and longitudinal movement in a position where it extends through the last mentioned opening to support the cutter therein, and a removable lock pin cooperating with the cutter carrying pin and a lug to retain the pin in position where the lugs cooperate with ythe notches.

5. In a core drill a head having a central core receiving opening and a cutter opening in its lower end spaced between the central opening and the exterior of the' head, the cutter opening having parallel inclined opposed walls, there being a slot in the head intersecting the cutter opening at right angles to said walls, the slot being open at the lower end of the head, longitudinally spaced fiat sided lugs on the walls of the slot, and a detachable cutter unit including a pin and a cutter rotatable-on the pin, the pin having fiat sided notches, said lugs cooperating with the notches to hold the pin against movement in a position where the cutter is rotatablein the opening and projects from the lower end of the head, the pin and cutter being adapted to be handled as a unit, and removable means for locking the pin in said position.

6.: A core drill including a tubular one-piece head having a plurality of openings in its lower end, a plurality of detachable cutter units each including a pin and a cutter rotatable on the pin, and means detachably connecting the pins yof. the units with the head in positions where the pins support the cutters in the openings, said means including tapered lock pins extending through tapered eccentric longitudinal openings in the nrst mentioned pins and cooperating with notches in the head.

7. In a core drill, a tubular head having an opening in its lower end, and a slot intersecting the opening, longitudinally spaced lugs on the wall of the slot, a detachable cutting unit including a pin having an enlarged bearing portion, a cutter rotatable on the pin and its said bearing portion, and a thrust washer on the pin atl an end of the cutter, the pinhaving notches, the lugs cooperating with the notches to hold the pin in a position where the ,washer engages a wall of the opening and an end of the said bearing portion engages the opposite wall of the opening, and means for releasably holding the 4pin in said position.

8. In a core drill, a tubular head having an 'opening in its lower end, and a slot intersecting tion engages the opposite wall of the opening, and

means for releasably holding the `pin in said position, the slot being open at the lower end oi' the head whereby the assembly of the pin, cutter and washer may be applied toand detached from 9. In a core drill, a `tubular head having an opening in its lower end, there being a slot in the lower end of the head intersecting the opening, lugs on the walls of the slot, a detachable cutter unit including a pin, and a cutter rotatable on the pin, the pin having notches, the said lugs cooperating with the notches to hold the pin against rotation and longitudinal movement, there being a longitudinal opening in the pin. intersecting a notch, and means for detachably connecting the pin to the head including a lock member extending through the opening in the pin and cooperating with the lug in the said notch.

10. A core drill including a tubular head having a plurality of openings in its lower end,'the inner and outer walls of certain of the openings being inclined downwardly and outwardly and the inner and outer walls of the other openings being inclined downwardly and inwardly, there being slots in the lower end 'of the head intersecting the openings and being substantially normal to their inner and outer walls, longitudinally spaced lugs on the walls of the slots', and a plurality of detachable cutting units each including a pin having an enlarged bearing portion providing a thrust shoulder, and cutters rotatable on the pins and the bearing portions of the pins, the pins having notches, the -lugs cooperating with the notches to hold the pins against rotation and longitudinal movement, the ends of the bearing portions of the pins extending through the first mentioned openings engaging the inner walls of the openings and the bearing portions of the pins in the said other openings engaging the outer walls of the openings.

l1. In a core drill a head having an opening in its lower end, the opposing inner and outer. walls of the opening being inclined downwardly and outwardly, there being a radially extending slot in the head intersecting the opening and at substantially right angles to said walls, lugs on the 'walls of the slot at each side of the opening, and

a cutting unit including a pin, and a cutter rotatable on the pin, the pin having notches, said lugs cooperating with the notches to hold the pin against rotation and longitudinal movement .in a. position where the cutter is rotatable in the opening on an inclined axis.

12. In a core drill a head having an opening in its lower end, the opposing inner and'outer walls of the opening being inclined downwardly and outwardly, there being a radially extending slot in the head intersecting the opening and at substantially right angles to saidwalls, lugs on the wall of the slot at each side of the opening, and a cutting unit including a pin, the pin having an enlarged bearing portion between its ends presenting a thrust shoulder and a cutter rotatable on the pin and said bearing portion, the pin having spaced notches, the lugs cooperating with the notches to hold the pin against movement in position where the said bearing portion engages one of said inclined walls and the cutter is rotatable in the opening.

13. A core drill including a tubular head having an opening extending into its lower end, a cutter for operation in the opening, a pin extending through the opening and supporting the cutter for rotation, the pin having notches, the head having a slot intersecting the opening and carrying the opposite end portions of the pin, and lugs on the walls of slot cooperating with the said notches whereby the pin ties together the portions of the head at the opposite sides of the openlng.

JOHN H. HOWARD. 

